1. Field of Invention
This invention relates generally to aquariums, specifically to a water pump, aerator, and filter for an aquarium.
2. Description of Prior Art
A home or other aquarium comprises a transparent tank of water and one or more fish in the water for observation by the owner of the aquarium. The water must be artificially conditioned for the survival of the fish. Specifically, it must be cleaned or changed periodically to remove contaminants caused by waste products of the fish. Also (unless it is very shallow with few fish) it must be aerated and (unless it has only goldfish) it must be heated.
Hertofore many systems have been devised for conditioning (heating, aerating, and cleaning [filtering]) the water in an aquarium, but each has one or more significant drawbacks.
One such system, shown in U.S. Pat. No. 4,272,372 to Fonseca (1981) shows an aquarium where the water is pumped from the bottom up through the filter cartridge. This leaves the waste matter, which has been filtered out of the water, on the lower side of the filter, allowing it to remain in and thus continue to contaminate the water. Also the waste falls back into the water and recontaminates it when the pump is turned off. In addition, it is awkward and difficult to remove the contaminated filter for changing Further, when it is removed, the water in the filter spills and leaks, recontaminating the water, or requiring the owner to hold a dish (an awkward operation) to catch the runoff. Finally, the Fonseca device requires that a relatively large tube extend down into the fish bowl to accommodate the filter cartridge, thereby precluding use of the device in small jars, glasses, etc.
Bennett, Bliss, and New, in U.S. Pat. No. 3,891,555 (1975), show a filter comprising a plurality of replaceable annular filter cartridges in a dual-walled, submerged container. This device has many of the disadvantages of Fonseca's, and, in addition, is awkward and expensive to make and change.
Goldman, Goldman, and DiMarchi, in U.S. Pat. No. 4,152,263 (1979), show a heated water circulator, but it does not filter the water. Thus it must be used with an additional, separate filter, with all of its attendant disadvantages.
Gorsky, in U.S. Pat. No. 4,163,035 (1979), shows an aerator comprising an air pump, an in-the-tank aerator, and an out-of-the-tank filter. This device is awkward to install because of its many parts. Also it cannot be used with very small tanks or small jars and glasses because of its out-of-the-tank filter.
Gilkey and Gilkey, in U.S. Pat. No. 4,802,980 (1989), show a self-contained, in-the-tank filter and pump where the filtering medium is gravel, followed by charcoal and fibrous material. This system requires that a motor be placed in the tank, precluding its use in very small tanks or small jars and glasses. Also the motor creates a shock hazard.
Dockery, in U.S. Pat. No. 4,416,090 (1980), shows an air lift pump which forces water to flow through a filter at the bottom of an aquarium. As such, this device has many of the disadvantages of Fonseca's.
Isaacson and Herrin, in U.S. Pat. No. 3,816,026 (1974), shows an air-lift pump which draws water through an external filter bowl. It cannot be used with very small tanks or small jars and glasses because of its out-of-the-tank filter.
Conn and Cohen, in U.S. Pat. No. 4,033,719 (1977), show a water circulation and filter system in which an water-lift pump comprises an air tube which extends down through an water-lift tube. Air supplied to the air tube creates bubbles at the bottom of the water-lift tube. These bubbles rise, entraining water, and thereby pumping water up through and to the top of the water-lift where it passes an ultraviolet sterilizer and then goes back down into the tank via a filter. This arrangement is disadvantageous the filter is complicated to change and disassemble. Also the pumping action will continue when the filter is changed, tending to direct water at the person doing the changing, thereby making such changing messy and more time consuming. Further the air tube must be passed through the water-lift tube, thereby providing an insecure attachment so that the air tube tends to pull up and out of the water-lift tube, which tends to stop the pumping action. Finally this system requires that a bulb be placed in the tank, creating a shock hazard.
Lambo, in U.S. Pat. No. 3,821,514 (1974), shows a heating element arranged in a filter outlet passage. This device requires a large surface area and thus cannot be used in small aquariums.
Sesholtz, in U.S. Pat. No. 3,511,376 (1970), shows a filter arrangement with a heater disposed in the filter discharge passage. His device is very complicated to manufacture, having many parts, and requiring a large-volume tank.